Dan,
The pre-amp portion of your system has as much, or more, effect on your overall sound as does the amp. This is why people are asking about whether you plan to use your receiver as a pre-amp -- your receiver will continue to be a limiting factor. You might want to see if you can borrow an amp somehow to test with, and buy it only if it really gives improved sound. Perhaps a store in your area that sells used or demo equipment?
- Eric